Conventionally, in a manufacturing process of an organic EL element, patterning by an ink-jet method is used to form a light-emitting layer. The ink-jet method is suitable for forming a uniform thin film pattern in a micro area. The ink-jet method forms the uniform thin film pattern at a pixel region defined by a bank by ejecting drops of an ink composition (hereinafter, referred to simply as “ink”) containing an organic EL material into the pixel region and drying the ink.
When the above method is employed, a surface of the bank is subjected to, for example, a liquid-repellent treatment using fluorine plasma. As a result, the surface of the bank has low wettability to the ink and the ejected ink becomes less likely to overflow the bank and flow in an adjacent pixel region. Accordingly, high-definition patterning becomes possible.
Moreover, Patent Literature 1 discloses a technology for patterning a higher-definition light-emitting layer by: having a two-layered bank composed of a upper bank layer made of a liquid-repellent material and a lower bank layer made of a liquid-philic material; making the upper bank layer have low wettability to the ink so that the ink is less likely to overflow the bank; and making the lower bank layer have high wettability to the ink so that the ink easily stays in the pixel region.